| Abstract | Improvements to a Hilger gauge block interferometer, including a fibre optic feed for a traceable laser radiation, automatic wavelength selection, and a charge coupled device camera for fringe observation, were presented. The gauge measuring process is now semi-automated, computer controlled, more accurate, faster and easier to operate than the original design. The decrease in quoted uncertainty is due to an increase in the accuracy of fringe fraction determination, better temperature control and measurement, and a better undertanding and evaluation of the sources of uncertainty. |
